"The Bachelorette" might be over just after it's started. That's because Nick is back, and Kaitlyn is smitten.

Monday's episode began with J.J. throwing his former BFF Clint under the bus leading to one of the show's more explosive breakups. But just as the guys got Mr. "Villians gotta vill" out, Nick showed up when the group arrived in New York. Nick's arrival led Kaitlyn to not only reveal their past "social media" relationship, but also that she was letting him join the season.

Below, host Chris Harrison says he was "120 percent" questioning of Nick's "convenient" arrival, but explains why he knew Kaitlyn had to see this possible connection through. Plus: How will Nick get along with the guys? (Spoiler: not well.) And will Nick's "kiss, sex and tell" behavior from Andi's season resurface? Keep reading.

What did you make of J.J. and Clint's bizarre blow-up?
Chris Harrison:
Their relationship was already really hard for me to comprehend last week, and then watching this play out made it even more awkward and strange. When I was there, it was confusing and we were in the control room asking each other what in the world was going on between these two. Watching it back, I thought there would be some clarity, but I found myself speechless trying to describe what I was seeing. I don't know what J.J.'s motive was. I'll be interested to talk to him at the "Tell All," but I don't even know if I'll get answers to make it clear. Then, his reaction during the interview was mind-boggling and shows what level of emotion was involved.

"The Bachelorette's" Chris Harrison: I'm still not sure what to make of Clint and J.J.'s relationship

The men then go to New York where J.J. gets booed for saying "hoes" during the group stand-up comedy date.
Harrison:
J.J. doesn't seem to often think of others' feelings and the ramifications of his actions. But the date was fun. Doug E Fresh was cool and is an 80s icon that I'm more than old enough to appreciate. I thought the guys did pretty well considering, and they were all better than Kaitlyn. She loves to rap, but she doesn't rap well.

Nick shows up and Kaitlyn immediately looked smitten.
Harrison:
I felt the same way. As soon as I saw her face light up when she saw him, it was over, done. Nick knew he had Kaitlyn. You could see the smug look on his face. I know she went through the proper emotions of being torn and trying to sleep on it, but it's like when you know you're going to make a purchase, it's just a matter of when. The fact that she was willing to put the guys through all that let's you know how serious she is about Nick.

When did you find out Nick wanted to come back?
Harrison: When everything started to come together [with him wanting to return], we had already started production. We learned of this prior relationship that they had, and once we figured out he was in New York and we were headed there, we were like, "OK, this is where you can show up and talk to her and whatever happens, happens."

The Bachelorette's Chris Harrison: Kupah took a ginormous dump on Kaitlyn's night

You must have questioned his motives. Harrison: I would 120 percent question Nick's motives and the way it all went down. When they started talking, they didn't know she'd be the Bachelorette, but he had an idea. So of all people to track down it was Kaitlyn? It seemed too obvious and convenient. So, I was very leery of Nick coming back. But you have to leave it up to her because obviously there were feelings there.

The guys really took the news better than I had expected.
Harrison:
This group of guys, who are pretty fantastic, took it as well as they possibly could have. If anyone expects them to be happy with her decision, that's not real. I don't think any proud man at this juncture is going to be happy about another guy, especially Nick, entering the game. Everybody knows Nick and what he pulled and how he outed Andi and double-crossed her and was kissing and telling. However emotional it was or the reasons he did it, it wasn't a very gentlemanly or honorable thing to do. I wouldn't have been shocked if they all got up and left. I told Kaitlyn that was a real possibility that they would say, "Screw you, I'm leaving." But that says something about Nick that she was willing to risk that.

What was your advice to her?
Harrison:
I told Kaitlyn, "This is tough, but at the end of the day there's also no right or wrong thing in this situation. There's something that could make people feel better or worse, but that's not necessarily the wrong thing to do. If you're truly here to find love and Nick is possibly part of that, then don't you have to figure that out?"

While still deciding, she had a one-on-one with Jared. I don't see a connection there, do you? Harrison: First of all, that whole date, to have the Met shut down and the way we did the helicopter tour was ridiculous. That was a movie. To credit Jared, had he handled the Nick situation any differently, that date would have been a disaster. He handled it with such grace and was able to sway Kaitlyn away from worrying about Nick. He's a good guy and maybe they don't have the chemistry that she and Shawn do or she and Nick, but how well he treats her -- any woman would be attracted to a man like that.

And speaking of cool dates, the second group one was pretty awesome.
Harrison:
We did that with The Lion King too. I feel a little bad because people literally give their lives to this craft and to end up on Broadway, and Kaitlyn and Chris walk in and get to be on stage. But it's special we got to do it in any small part.

So, what can you tease now that Nick is here to stay?
Harrison:
We have a rose ceremony [at the beginning of next week]. Not only is the bomb of Nick coming in and living with them about to be dropped, but very shortly after, they'll have to deal with the fact that some of them are going home and Nick is not. Then we're off to San Antonio, Texas, and that's when the real drama begins. The relationships are tested and some of them quickly don't work. And in true Nick fashion, he doesn't try to ingratiate himself with the guys. He could come in and be humble, but he's not. He has this skill to just rub people the wrong way.

I'm curious to see if Kaitlyn calls him out on what he did to Andi.
Harrison:
Or if history repeats itself. I think we all have this ability to think, "Oh that won't happen to me." And then guess what?

"The Bachelorette" airs on Mondays on ABC.